A pro-euthanasia campaigner is delighted Evans Mott has avoided conviction for helping his wife to die, but says the law still needs to be changed.

Mott, 61, was discharged without conviction after previously admitting a charge of aiding and abetting the death of his wife Rosie, who suffered from an aggressive form of multiple sclerosis and committed suicide at their Auckland home.

Crown lawyers at the High Court in Auckland had sought a sentence of home detention or community detention.

But Justice Patricia Courtney said Mott's involvement in his wife's death was on a low scale, and the master boat-builder's work prospects in the United States, where he had worked several times previously, could be impacted.

Rosie Kaplan, the Auckland secretary of the pro-euthanasia campaign group End of Life Choice, was delighted with Justice Courtney's decision, saying Mott had been a loving and supportive partner.

But she says the special circumstances in Mott's case meant the decision wouldn't result in "open slather" and she hopes a members' bill currently waiting to be drawn out of the Parliamentary ballot is passed.

"There are lots of people who are sick and lots of people are happy to continue to be sick ... but for some people their quality of life is just so low that they want to make their own choice to end their own life when they want to end it."

Mott, who helped in the construction of a superyacht for billionaire Graeme Hart, helped his wife research suicide methods and prepare a kit last September.

On December 28 Mrs Mott, who was suffering from tremors, incontinence and difficulty walking, asked her husband to leave their Orakei home, which he knew meant would be the last he saw of her as she didn't want anyone thinking he'd directly helped her die.

A tearful Mott said outside court that the decision "couldn't be a better legacy for Rosie".